The present invention relates generally to virtual reality, and more particularly to the generation of realistic audio for one or more participants of a virtual reality simulation.
Audio entertainment has progressed from the era of live performances to recorded performances stored on such media as records, tapes, compact discs (CDs), digital memories, etc., and played back on such devices as the Edison phonograph, the gramophone, the tape recorder, the CD player, digital players (e.g., MP3 players), and wireless receivers, many of which include two or more channels of stereophonic sound. Video entertainment has similarly progressed from the era of live performances to that of recorded performances. Over time, recorded videos have been stored for playback on such devices as the Magic Lantern, the cinematograph, the television receiver, the VCR, and the CD/DVD, none of which, by contrast with sound, have made much use of stereoscopic or 3D vision. Nevertheless, stereoscopic vision is well known, and stereoscopic goggles, also known as 3D or virtual reality goggles may be purchased, for use with various video formats, e.g., computer games.
The term “virtual reality goggles” is often mistakenly inter-changed with the term “3D goggles.” However, conventional 3D goggles lack an essential feature that distinguishes real virtual reality from mere 3D. When a viewer uses 3D goggles, the image presented to each eye is computed independently of the real location and/or orientation (yaw, pitch, and roll angles) of the viewer's head. Consequently, the scene appears fixed in relation to the goggles, instead of fixed in external space. For example, if the viewer's head tilts to the left, all objects appear to tilt to the left, which violates the signals the user receives from his/her balance organs and destroys the illusion. Real virtual reality aims to correct this deficiency by providing a head position sensor with the goggles, from which the actual position (location and orientation) of each eye may be determined. No particular technological solution for this has been standardized.
Providing realistic images to each eye based on a position of the eyes requires a large amount of real-time computing. For example, virtual reality may require updating a panoramic image of 2048×1024 pixels for each eye every few milliseconds in dependence on the location and orientation of each eye. Such an enormous amount of real-time computing typically required virtual reality demonstrations to be performed in the laboratory. However, the power of affordable computers has increased many-fold since the first real-time virtual reality demonstration approximately 15 ago. Also, the recognition of the existence of common computations in some virtual reality scenes has helped reduce the computational cost. For these reasons, and because of the greatly improved experience of virtual reality over mono-vision or even over 3D vision, virtual reality may become affordable and desirable in the mass entertainment market at some future time.
Virtual reality generally requires a delay of only a few milliseconds between receiving head position signals and delivering a 2-megapixel image to each eye. Such requirements make it unlikely that the virtual reality experience may be provided in real time from a distant source, such as over the Internet or by television broadcast, for example. The processor(s) that implement a virtual reality simulation should therefore be located close to the virtual reality participant. As such, the real-time requirements of virtual reality should make it attractive to businesses that provide entertainment to multiple co-located individuals, e.g., cinemas.
Because virtual reality is still in its infancy, many details are still under investigation, such as the best technology for providing head location/orientation information, and the best way to generate realistic virtual reality audio to complement the virtual reality imaging. Thus, there remains a need for further improvements to existing virtual reality technology.